There are striping apparatus technologies of circular knitting machines well known to people, such as U.S. Pat. No. 6,655,176 “Striping Apparatus For Circular Knitting Machines” and U.S. Pat. No. 5,070,709 “Striping System For Circular Knitting Machine”, which respectively disclose striping apparatuses feeding different yarn into the knitting needle of a knitting machine. Besides, U.S. Pat. No. 5,218,845 “Circular Knitting Machine Striper Control System” discloses a controller for a striping apparatus.
As shown in from FIG. 1A to FIG. 1D, the striper structure of the abovementioned U.S. Pat. No. 5,218,845 comprises: yarn-changing plates 10; movable blades 11; and drive elements (not shown in the drawings), used to drive the yarn-changing plates 10 and the movable blades 11. In normal state, the yarn-changing plate 10 is at a non-enable normal position, and the movable blade 11 also withdraws back to the main body 12, and a hook 110 clips the yarn to position at the front edge 120 of the main body 12. As shown in FIG. 1B, when the machine begins to feed yarns, the drive element pushes the yarn-changing plate 10, and then, the front end of the yarn-changing plate 10 extends outward. Simultaneously, the rear end 101 of the yarn-changing plate 10 touches a first pin 111 of the movable blade 11 to drive the movable blade 11 toward the left side of the FIG. 1C until the yarn-changing plate 10 reaches an external yarn-feed position, and then, the hook 110 of the movable blade 11 releases a yarn Y, as shown in FIG. 1C. Naturally, before the hook 110 releases the yarn Y, the yarn-changing plate 10 has transferred the yarn Y to the yarn-feed position, and a knitting needle 13 hooks the yarn Y to perform knitting operation.
Lastly, when yarn is intended to change, the yarn-changing plate 10, which has reached the external yarn-feed position beforehand, will be pulled by the drive element back to the normal position, as shown in FIG. 1A. During the process that the yarn-changing plate 10 moves to the right side of FIG. 1D, a nose 102 of the yarn-changing plate 10 will touch a second pin 112 of the movable blade 11 and actuate the movable blade 11 to move rightward and back to the normal position, and then, the hook 110 of the movable blade 11 will cut off the yarn Y and clip the tail of the yarn Y at the front edge 120 of the main body 12.
In general, such a striping apparatus can provide multiple different colors of yarns; for example, the four-color striping apparatus has four sets of parallel-arranged yarn-changing plates 10 and movable blades 11 to change four kinds of yarns respectively, and it is the same for the six-color striping apparatus; the more the number of yarns, the greater the width of the striping apparatus. In the striping apparatus disclosed in the abovementioned U.S. Pat. No. 5,218,845, as the movable blade 11 is driven by the yarn-changing plate 10, the time that the yarn-changing plate 10 touches the second pin 112 of the movable blade 11 is later than the time that the drive element begins pushing the yarn-changing plate 10 toward the normal position. Such a design that both the yarn-changing plate 10 and the movable blade 11 are driven by an identical drive element will bring about the delay of the time that the movable plate 11 cuts off the yarn Y. In such a design that both the yarn-changing plate 10 and the movable blade 11 are driven by an identical drive element, when an old yarn and a new yarn, e.g. a yarn 1 and a yarn 6, are spaced farther, the time difference between two actions increases because of the larger spacing therebetween, and the time of releasing the yarn Y is too late so that the yarn will be torn off when the tail of the yarn is still clipped by the movable blade 11 and a yarnlet Y1 will still remain clipped, as shown in FIG. 1B; then, the yarnlet Y1 will be released and tangled with fabric; therefore, fabric quality is degraded.